Shock absorber: How the component dampens vibrations and how to change it

The car’s shock absorbers effectively dampen vibrations and thus make a significant contribution to driving safety. The effective vibration dampers are found in the area of the chassis. Together with the suspension, they act as a connecting element between the wheel suspension and the body. If a shock absorber is defective, symptoms such as spongy handling or unusual noises when the road surface is uneven often occur. Since defective shock absorbers endanger driving safety, they should be replaced as soon as possible.

A shock absorber is a damping element in the area of the chassis, which is present once per wheel in most cars. The cylindrical component is installed between the body and the wheel suspension and, together with the vehicle spring, ensures increased driving stability. In many cars, the shock absorber forms the suspension strut together with a coil spring.

The car’s shock absorbers reduce the vibrations that occur during driving, for example when braking or driving over bumps in the road. Strictly speaking, a shock absorber is not a shock absorber but rather a vibration damper. However, the term shock absorber has become generally accepted for the dampers of the chassis.

How modern shock absorbers work

Modern shock absorbers are highly developed car parts, which today are mostly installed in the form of gas pressure dampers. Depending on the type of shock absorber, either the twin-tube or the single-tube principle is used. As telescopic shock absorbers, the components have a damper piston that moves up and down in a cylinder and is damped accordingly.

The movements of the chassis are effectively damped depending on whether the suspension is compressed or released. The same applies to the vibrations that occur during driving. Due to the heavy loads, shock absorbers often wear out more than other chassis components. Many drivers do not notice the constantly decreasing damping, but unconsciously adjust their driving style.

How long does a shock absorber last?

How long a shock absorber lasts before it breaks down depends on numerous factors. Among other things, the shock absorber design, the usual use of the car and the kilometres travelled have a direct influence on the durability of the shock absorbers. For example, a sporty driving style or driving at high speeds shortens the life of the shock absorbers.

If a car is frequently driven on bad roads with many bumps, the shock absorbers also wear out more quickly. Frequent driving with a trailer can also stress the shock absorbers. The same applies if a vehicle is regularly used with a high load. Last but not least, weather influences or loads such as road salt in winter can affect the service life of the shock absorbers.

Common symptoms of a defect in the shock absorbers

• Vehicle stands out due to spongy handling
• Steering flutters or vibrates
• Noises like rumbling of the undercarriage
• Car clearly swings after bumps
• Tyres wear faster or unevenly
• Leakage of damper oil at the shock absorber

To replace shock absorbers on the vehicle

If the shock absorbers are worn or defective, they must be replaced with a suitable spare part. Skilled car mechanics sometimes carry out this work themselves. The exact procedure and the time required vary depending on the vehicle and depend, among other things, on the installation position and the type of shock absorber mounting.

Depending on the vehicle, changing the rear shock absorbers can be much easier than changing the front shock absorbers. This is because the chassis of modern cars is often designed as an independent suspension with a spring strut. Since the shock absorber and spring are combined, the entire suspension strut must be removed to replace the shock absorber.

Change front shock absorber

Sometimes, for example, parts of the steering have to be dismantled in order to change the front shock absorber. After jacking up the car, the corresponding wheel is removed so that the suspension components can be accessed. Then, depending on the vehicle, the brake caliper must be removed and the drive shaft loosened.

To be able to remove the suspension strut with the shock absorber, it is often necessary to separate the steering knuckle from the wishbone and also to remove the coupling rod. Finally, the screws on the strut mount that connect the shock absorber to the body are loosened. The shock strut can now be removed in order to replace the front shock absorber.

Install new shock absorbers

In order to change the shock absorber, the corresponding strut must be disassembled. To do this, the spring is tensioned with a spring compressor and the screw connection on the shock absorber is loosened. The shock absorber can then be reassembled with an intact shock absorber and installed in the vehicle in reverse order.

If the vehicle spring is already worn out, it is a good idea to replace it as well. The same applies to the bump stop, as this component is already available at a reasonable price. If the shock absorbers on the rear axle are replaced, the amount of work is usually less. Due to the way the shock absorbers are attached, only a few bolted connections need to be loosened and tightened again.

These are the five biggest dangers of defective shock absorbers

1. Longer braking distance: The braking distance can increase significantly when the damping decreases.
2. Crosswind sensitivity: The car becomes sensitive to crosswinds and may rock.
3. Risk of skidding: Without the reliable function of the dampers, the vehicle can skid more easily.
4. Poor road holding: When cornering, the car behaves spongily and can swerve more easily.
5. Lack of grip: The car loses grip on bumps and when going over crests.

Buy matching telescopic shock absorbers for your car

If the car’s shock absorbers are defective, they should be replaced promptly with suitable spare parts. If you do not want to buy completely new shock absorbers, you can use used original parts at a favourable price. It is important that the shock absorber type matches the shock absorbers installed on the vehicle.

Shock absorbers for the front wheel suspensions usually have a spring plate that holds the corresponding suspension spring. Used shock absorbers are often offered together with the matching spring. If you want to change both shock absorbers of an axle, a complete shock absorber set with two dampers is the best solution.

At Autoparts24.eu you will find numerous spare parts from environmentally friendly car recycling at a favourable price. If you would like to buy used car parts such as shock absorbers, you can easily search for suitable items using the key number from the vehicle registration document. The OEM number, which is stamped or printed on many car parts, is also helpful in the search. Thanks to additional product illustrations, you can easily identify the shock absorber type and the intended shock absorber mounting method.